In his ruling party's landslide victory in weekend parliamentary polls, Ethiopia's prime minister Meles Zenawi saw an enthusiastic popular endorsement of polices that are gradually leading the country out of poverty and backwardness. But western observers and human rights groups saw something quite different: the alarming advance, mirrored in other African states, of what might be termed one-party democracy.

Meles's Ethiopian People's Revolutionary Democratic Front, in power since 1991, and its allies won about 97% of parliamentary seats, assuring it another five-year term. Opposition groups were decimated. With most results in, the eight-party Medrek (Forum) coalition, the All Ethiopia Unity Organisation, and the Ethiopian Democratic party took only two seats between them, despite fielding candidates in most constituencies.

The comprehensiveness of Meles's victory seemed to take even the government by surprise. It quickly recovered. "Logic dictates that the party was bound to succeed. In democracies a government with a sound track record remains in power … There is therefore no room for anyone, be it the contesting parties or the international media, to reiterate alleged irregularities and rigging of votes," an official statement said.

Berhanu Kebede, Ethiopia's ambassador in London, said voters had rewarded Meles for his achievements. "The government has registered successful development and growth polices. There has been double-digit growth for the past seven years. Primary school and health sector coverage have greatly improved. There has been more investment in infrastructure in the past 10 years than in the previous 100," he said.

In contrast to the ruling party's "mature and experienced leadership", the opposition was disorganised and lacked a clear strategy and policies, Berhanu said. It had comprehensively lost a series of nine televised debates on healthcare, foreign policy and other issues. He dismissed concerns expressed by EU poll observers about the lack of a "level playing field" and accused Human Rights Watch, an independent human rights advocacy organisation, of pursuing a hostile agenda and relying on "hearsay".

In a hard-hitting report this week, Human Rights Watch said the government "intimidated voters and unlawfully restricted the media" prior to the polls and employed "repressive legal and administrative measures" to restrict freedom of expression. Its findings echoed complaints by Medrek during the campaign that its candidates had been harassed, some had been jailed, and three members had been killed.

Government critics claim the opposition's poor showing is a product of a crackdown that followed the last polls in 2005, when about 200 people died in post-election unrest, opposition leaders were jailed, and the then main anti-government alliance, the Coalition for Unity and Democracy, later broke up in disarray. The hope of political change was stifled during that period, it is argued, and has yet to revive.

Though still unwelcome to the government, European and US criticism has been muted, reflecting a mutual interest in maintaining counterterrorism and other co-operative ties with Meles, who is widely seen as the sort of African leader the west can do business with. "While the elections were calm and peaceful and largely without any kind of violence, we noted with some degree of remorse that [they] were not up to international standards," Johnnie Carson, the top US diplomat for Africa, said.

But Carson hastened to add that Washington valued its relationship with Ethiopia and "appreciate the level of collaboration we receive". The US views Ethiopia as crucial to maintaining stability and countering Islamist extremism in the Horn of Africa, notably in neighbouring Somalia. Like other western countries such as Britain, a major bilateral aid donor, the US is highly unlikely to take any action over election irregularities, real or imagined.

Hard-nosed calculations of this type inform western approaches to other African "one-party democracies", an attitude that could be said to encourage the trend away from genuine multiparty systems, thereby undermining the drive for good governance. But the problem is rooted in Africa itself. One analyst dubbed the trend "winner-takes-all politics". And it is spreading.

In Uganda, President Yoweri Museveni, once hailed as an African democratic role model, appears, Mugabe-style, to have installed himself in office for life. In Burundi and Rwanda, the runup to elections this summer is following a familiar pattern: alleged increased ruling-party repression and intimidation of opponents, media restrictions, and reduced access for independent observers and NGOs. Even in South Africa, self-styled continental showcase, political life is dominated by one party, the African National Congress. It is difficult to envisage conditions in which the ANC would voluntarily relinquish power.

In Congo, meanwhile, observers suggest mounting official pressure on the UN peacekeeping force to withdraw is linked to the government's wish to avoid too close international scrutiny of next year's presidential and parliamentary elections. "The consolidation of democracy in the Democratic Republic of Congo is stalled on almost all fronts," a recent International Crisis Group report warned. "Civil liberties are regularly threatened and key institutional reforms … have made no significant progress."

The Africa Progress report, published this week to mark Africa Day, highlighted the importance of legitimate governance. "Africa's development and the welfare of its people depend above all upon the political commitment and capacity of its leaders," it said.

Speaking recently in Cameroon to mark 50 years of independence from colonial rule of a cluster of African countries, Kofi Annan, chairman of the panel that produced the progress report, remained optimistic about Africa's prospects overall but suggested too many of those same leaders were falling down on the job: "There are still too many instances of corruption, of elite capture of resources, of growing inequality in work and opportunity, abuse of electoral processes and selective adherence to the rule of law."